The folder “.MagicBox” is with dot what means, in linux meaning, hidden folder, and because android is created from linux then system understand it. And is hidden because it protects against malicious cleaner applications, which mostly leave folders with dot untouched. People installed master cleaner or similar apps which deleted “unused files and folders”, include game profiles.
If you connect your device to pc then is probably connected through MTP protocol. Android has this protocol buggy many years and does not fix it. For example if you connect phone to windows system then windows should rescan your phone and build files and folders structure, but it does bot work correctly and result is that some files are not shown. There is small trick which can help, if is your device connected to pc, then on your phone open file manager and find file which you need copy. In file manager press cut and paste it to another folder like Pictures, now you should see that file in windows.
If your file manager filters folders and files with dot then maybe it can be turned off in options. Or install total commander from market, or es file explorer
But you still can press “share” during export and pick file manager to save